Gross glassy density is defined as a blurred dense image on high-resolution CT in which bronchial structures or pulmonary vasculature can still be seen. Most early-stage lung cancers have not yet become dense, so there is a high prevalence of vacuolar and bronchial gas signs, and a significant proportion of nodules with gross glassy density (GGO). In a lung cancer screening, 19% of the non-calcified nodules were GGO, of which 18% of the simple hairy glass nodules were lung cancer, 63% of the complex hairy glass nodules (i.e., with small nodular dense areas) were lung cancer, and only 7% of the solid nodules were confirmed to be lung cancer, which is enough to show that the nodules found in the screening test, especially the inhomogeneous hairy glass nodules, should be paid special attention. Nodules of 10 mm can be reviewed in 3 months, while those of more than 10 mm should be reviewed once a month; according to the density, simple GGO should be followed up in half a year, mixed GGO in 3 months, and solid nodules in 1 month. ~Nakata found 34 cases of lung cancer and 9 cases of adenomatous hyperplasia in 43 cases of GGO. There is another reason why we need to pay special attention to GGOs. Since lung cancers that manifest as GGOs are early-stage lesions and have a relatively long doubling time, and 100% of them survive for more than 5 years after surgical resection, the correct judgment of detected GGOs is crucial for the early diagnosis of lung cancer. The change of nodule size is also important for the judgment of the nature, in most cases, the nodule doubling time is less than 1 month or the stabilization time is more than 24 months should be regarded as benign, so to say, if the examination found SPN, and less than two months ago did not show the nodule on the right photo, or found nodule 24 months basically no change, then it is less likely to be malignant. the interval of SPN follow-up is often depending on the The size and density of the nodule, generally the larger the nodule, the shorter the follow-up time should be, the more soft tissue density components in the nodule, the shorter the follow-up time should be. 5mm or less can be reviewed in six months, 5-10mm can be reviewed in three months, 10mm or more is best to be reviewed once a month; according to the density of the simple GGO half a year follow-up, mixed GGO 3 months follow-up, solid nodules 1 month follow-up. According to the density, simple GGO should be followed up in half a year, mixed GGO in 3 months and solid nodules in 1 month. In general, it is believed that if there is no change in the lesion on CT after 3 months, it may be a tumor or focal interstitial fibrosis, and surgical resection is appropriate.MNGGO is mostly adenocarcinoma or adenocarcinoma combined with alveolar carcinoma, and should be operated early. If the lesion increases in size during the follow-up period, or if there is a realistic component in PNGGO, it is usually due to a tumor and should be operated immediately.